In a word: No
In two words, Hell No.
When Limbaugh hit bigtime, probably a third of all the "conservative" local talk hosts who suddenly popped up around the country were previous liberals posing to try to get or keep a job. Some claimed to have "saul-on-the-road-to-damascus" conversions, others just counted on changing locales or short memories.
Case in point, Mike Siegel.
Another case in point, Steve Kane in Miami -- not that it's helped him get a real talk radio gig as opposed to brokering time.